JPH06214104A - Reinforced capsule lens-type recursive reflection sheet - Google Patents

Abstract

PURPOSE: To provide a capsule lens-type recursive reflection sheet. CONSTITUTION: The reinforcing capsule lens-type recursive reflection sheet contains the layer 11 of connection acid where recursive reflection constitution elements are partially embedded on an upper surface, a transparent cover sheet positioned with a space from the layer of the recursive reflection constitution elements, mesh connection lines with small width which connect the layer 11 of connection acid and are constituted by containing connection acid which is embossed from the layer 11-side of the connection acid forming multiple cells where the recursive reflection constitution elements are closely sealed and is brought into contact with the cover sheet, and a reinforcing sheet 16 which is permanently and directly fitted to the base of the connection acid, is embossed with the layer 11 of connection acid and follows an emboss form at the base of the layer 11 of connection acid.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention allows a capsule lens type retroreflective sheeting (described in U.S. Pat. No. 3,190,178) and, in particular, such sheeting to be integrated into garment worn by pedestrians. As described above, the present invention relates to a capsule lens type retroreflective sheet in the form of being integrated with a reinforcing sheet or a reinforcing cloth.

[0002]

2. Description of the Related Art A capsule lens type retroreflective sheet is characterized by providing high-brightness retroreflectivity and maintaining its reflectivity even when wet with water. Such seats are provided in a flexible fabric reinforced form for attachment to clothing, which has the advantage of making pedestrians wearing clothing attached to such seats more visible to the driver of the vehicle at night. Because the sheet has a reinforcing fabric, it can be easily sewn on, attached to, or otherwise integrated with the garment.

[0003]

However, existing fabric-reinforced capsule lens type sheets have the following problems. That is, it is generally accomplished by using a pressure sensitive adhesive to attach the reinforcing fabric to the bottom surface of the sheet, but the reinforcement by this results in a thicker product, and
There is a problem that the clothing is unnecessarily stiffened.
Further, there is a problem that the manufacturing cost is increased because a step of applying the pressure sensitive adhesive and a step of laminating the cloth are required. In addition, the adhesive may ooze out from the gaps in the fabric, especially under the pressure that occurs when the sheet is wound around the storage roll, which results in (blocking) adhesion between adjacent winding fibers on the storage roll. Also, there is a problem in that the surface of the sheet may become dirty.

[0004]

The present invention provides a novel reinforced capsule lens type retroreflective sheeting that alleviates the above problems, and the present invention also provides a novel method for making such sheet. Briefly, this novel method involves (1) creating a layer of binder on the top surface that is partially embedded with a retroreflective component (the "top surface" is acceptable for reflection). The outer surface of the sheet on which light is incident, or, with respect to the lower layer constituent material of this sheet, means the surface facing the same direction as the uppermost outer surface; "bottom surface" means the surface opposite to the upper surface. (2) attaching a reinforcing sheet to the bottom of this layer of binder; (3) overlaying a transparent cover sheet over the layer of this retroreflective component; and (4) to the bottom of this reinforcing sheet. Applying a reticulated heat and pressure in the direction, whereby the reinforcing sheet is embossed, and also from the layer side of the binder so that the binder partially contacts the cover sheet along the mold. ,,. This embossing step forms an integral article in which the binder layer and cover sheet are bonded together and a number of cells are formed in which the retroreflective components are hermetically sealed. The binder layer has an embossed shape, and the reinforcing sheet follows this embossed configuration. Preferably, the reinforcing sheet is laminated on the bottom surface of the binder layer by heating and pressing before applying embossing heating and pressing.

A novel sheet was produced by the method described above, which is briefly described as follows: (1) a layer of a binder with a retroreflective component partially embedded on the upper surface; (2) this retroreflection. A transparent cover sheet located at a space from the layer of the reflective reflective component; (3) bonding the binder layer and the cover sheet together, and hermetically sealing the retroreflective component therein. Forming a large number of cells which are embossed from the side of the layer of binder and which comprises a binder that is in contact with the cover sheet and has a narrow mesh of connecting lines (of this binder layer). The embossing leaves an embossed shape on the bottom surface of the binder layer); and (4) permanently and directly attached to the bottom surface of the binder layer and together with the binder layer. Reinforced embossed to follow the embossed shape of the bottom of this layer of binder Comprising; over bets. Preferably, the reinforcing sheet comprises a fabric, so that the binder derived from the layer of binder penetrates the weave of the fabric to enhance the adhesion of the fabric to the layer of binder. .

A typically finished sheet 10 of the present invention is depicted in a top view in FIG. 1 and in its enlarged view in cross-section (along line 3-3 in FIG. 1). There is. As depicted, this exemplary sheet 10 has a base layer 11 of binder; partially embedded on the top surface of the layer 11 of binder, and with its embedded or bottom surface Transparent microspheres 12 covered with a vapor-deposited mirror-like reflective material 13.
(The specular reflective material is typically aluminum or silver deposited on the microspheres, or B
A dielectric material, such as those described in U.S. Pat. No. 3,700,305 to Ingham; a combination of the microspheres and a specularly reflective material, the retroreflective component being supported in a binder. A transparent cover sheet or topsheet or film 14 which is placed over the microspheres 12 and is impressed from the layer 11 of binder through the microspheres 12. Film 14
Bound to this layer of binder by means of a mesh-like narrow bond line 15 comprising a binder which is partially adhesively connected to the binder layer; It comprises a reinforcing sheet 16 conforming to the embossed shape of the layer of agent; and a protective film 17 which can be included if necessary as explained below.

In making the sheets of the present invention, the microspheres 12 are generally first coated with a carrier sheet, such as polyethylene coated paper (Mckenzie US Pat. No. 3,19,19).
(See No. 0,178) for partial embedding in a removable manner. The surface of the microspheres protruding from the carrier sheet is covered with a specular reflective material by vapor deposition. A representative carrier sheet 18 is depicted in Figure 2 and includes a paper sheet 18a and a polyethylene layer 18b.
An intermediate product of microspheres embedded in a carrier sheet and covered with a specular reflective material is shown in FIG.
Write.

Next, a binder derived from a solution or a melt is applied onto the specular reflecting material, or a layer of binder preformed on the microspheres is placed by heat and pressure. (Bailey et al., US Pat. No. 5,064,272, column 5, lines 61 to column 6,
See line 17; this latter method has the effect of not overly embedding the microspheres on the carrier sheet; thus, when the carrier sheet is subsequently separated from the layer of binder, the The specular reflective material tends to remain on the carrier sheet and does not cover the surface of the binder layer between the microspheres, which reduces the impact on products based on the metallic specular reflective material. ). By the binder drying or cooling step, the binder layer 11 is partially embedded with the microspheres in the binder layer 11 and also in the carrier sheet. The result is construct 20 of FIG.

In the preferred practice of the invention, a reinforcing sheet 16 is then laminated to the bottom surface of the layer of binder. Such lamination may be performed later, for example, after peeling the temporary carrier sheet 18. However, when laminating is done, this assembly should be reinforced with the carrier sheet where it should be. Lamination is preferably reinforcement sheet 16
Is pressed against the layer of binder 11 and then the assembly is pressed and heated through a pair of rollers (parts 21 and 22 shown in FIG. 2, at least one of which is heated). .

The reinforcing sheet 16 is preferably a cloth,
And during the laminating process, a portion of the layer 11 of binder penetrates into the weave of the fabric, which causes the fabric to bond tightly with the binder or, if there is a large gap in the fabric, to penetrate. In order to prevent the binder from soiling the laminating roller, the protective film 17 may be removably attached to the bottom surface of this reinforcing fabric. One useful protective film is
A two-layer film comprising a heat-softening layer 17a, for example polyethylene, and a non-heat-softening layer 17b, for example polyethylene terephthalate, which can be heat laminated on a reinforcing fabric. The film 17 may be bonded to the reinforcing fabric and left as part of the final product, or the fabric may be integrated into the garment or stripped prior to other uses of the product.

Next, in the preferred method illustrated, the carrier sheet 18 is stripped to expose the microspheres protruding from the layer 11 of binder. A cover film 14 is placed on the surface of the protruding microspheres and the resulting assembly is subjected to a stamping process as shown in FIG. The entire assembly comprising cover film 14, binder layer 11, reinforcing sheet 16 and protective film 17 is inserted between a pair of heated platens or rollers, 24 and 25. One platen or roller (25) is an embossing platen with a raised ridge 26 pattern. The ridge 26 on the embossing plate pattern is pressed against the bottom of the protective film 17 to deform the protective film, the reinforcing sheet 16 and the binder layer 11 into the shape shown in FIG. The binder layer 11 is sufficiently heated and pressed so that the microspheres in the pressed area are flooded with the binder and it comes into contact with the cover film 14 to provide the bond 15. The ridge pattern on the embossing plate is such that the mesh-like narrow connecting lines 15 shown in FIG. 1 are formed. This bond line 15
Are crossed to define cells 27 that are hermetically sealed therein, but various other patterns are also available; for example, a hexagonal pattern may be used instead of the square pattern of FIG. You can also

As the cover film useful for integrating with the capsule lens type retroreflective sheet, known cover films can be used. In the reflective sheet of the present invention, a polyolefin-based film having good flexibility even in a low temperature environment is particularly desired, and specifically, polyethylene, polypropylene, ethylene-acrylic acid copolymer and the like are used. The inclusion of UV absorbers is desirable, especially in polyolefin-based films, to avoid degradation of the film and underlying components during field exposure. Furthermore,
The described polyolefin-based film does not have the desired resistance to penetration by microspheres during the embossing process shown in FIG. 3, and therefore is described in US Pat. No. 5,066,098 (incorporated herein by reference). It is also possible to have a hardened layer or coating (not shown) of a softening agent as described in. Specifically, a layer made of a polyurethane resin such as an aqueous colloidal urethane dispersion or an acrylic emulsion can be used as a hard material. A suitable commercial material is NeoRez under the trade name Polyvinyl Chemical Industries
(Polyurethane) or NeoCryl (acrylic).

The layer or coating of the above-mentioned harder softening agent can also enhance the adhesive force between the cover film and the binder which is embossed and is in contact with it. Further, these layers may be colored by including an appropriate coloring material.

In addition, a highly plasticized polyvinyl chloride film can be used as the cover film of the present invention.

In general, the binder that can be used in the reflective sheet of the present invention should have a glass transition temperature (Tg) of, for example, -20 ° C or lower in order to maintain good low temperature characteristics. Thermoplastic polyurethane polymers are particularly useful as the binder layer 11, which provide good durability and flexibility, including flexibility at low temperatures. Aromatic polyurethanes are susceptible to coloring or bleaching in sunlight, but the addition of hiding pigments, such as titanium dioxide, avoids any coloring or bleaching of the product. White coloring is generally desired to minimize the gray or metallic color produced by the metallic coating on the microspheres. Addition of such titanium dioxide is also effective for whitening.

Ethylene-acrylic acid polymers are another useful polymer in binders. When a cover film using ethylene-acrylic acid polymer is used in combination with a binder using ethylene-acrylic acid polymer,
No polyurethane hard layer on the cover film is required to achieve good bonding to the cover film.

The binder can also include a mixture of polymeric materials and other ingredients. For example, it is appropriate to mix a vinyl chloride / vinyl acetate copolymer with a polyurethane polymer to provide durability and flexibility. Also, stabilizers and antioxidants can be added to enhance durability. Furthermore, the addition of fluorescent dyes is also useful in providing bright visible colors.

Fabrics are particularly useful as the reinforcing sheet of the present invention because they are durable and have high tensile strength; the binder penetrates the weave of the fabric to provide good adhesion. Because it can be reached; since it is possible to use a plasticizer-free fabric which can give rise to the problem of weakening the adhesion. Polyester spunbond fabrics are also particularly useful;
It typically comprises a bicomponent fiber having a polyethylene terephthalate core and a polyethylene or polyester outer layer that softens at a lower temperature than the polyethylene terephthalate core. Polymer films impart alternativeness to fabrics for several purposes.

In the reflective sheet of the present invention, for example, a protective film 17 can be provided, but a suitable resin is thinly applied or calendered on the bottom surface of the cloth (the surface opposite to the surface bonded to the binder layer). By applying the above, it is possible to narrow the gap of the cloth and avoid the protective film. For the cloth, a material with high adhesive strength to this binder should be selected. In practice, however, the reinforcing film is subjected to physical treatment such as corona treatment in order to enhance the adhesive strength. You may

The final product of the invention is thin, lightweight and flexible, which stretches well at low temperatures such as below -20 ° C. Preferably the finished product is 32 without protective film.
It has a thickness of 5 micrometers or less, and it is sufficiently flexible that it has a diameter of 3 millimeters (0 ..
It can be easily wrapped around a 125 inch mandrel. The reinforcing sheet conforms to the embossed shape of the bottom surface of the binder layer and therefore has no space for water to collect. In addition to being integrated with clothing, the reflective sheet of the present invention can also be used alone as a sign board that is unwound from a storage roll and attached to a required location, such as the rear of an automobile.

The invention is further described in the following examples.

[0022]

EXAMPLE A carrier sheet 18 in which a solution of a binder prepared from the following components is embedded in microspheres 12 with an average diameter of 65 micrometers up to about 30% of its diameter and covered with evaporated aluminum: It was applied onto an intermediate product sheet 19 comprising.

Parts by weight thermoplastic polyurethane resin ¹ 16.99 vinyl chloride / vinyl acetate copolymer ² 6.73 titanium dioxide ³ 7.00 antioxidant ⁴ 0.48 stearic acid 0.48 methyl ethyl ketone 49.49 cyclohexanone 17.88 ¹ Elast ET1145 commercially available from Takeda Verdish Urethane Industry Co., Ltd. Tokyo; reaction product of methyl diisocyanate and polyester type polyol comprising tetraethylene glycol and adipic acid; number average molecular weight 140,000 and weight Average molecular weight is 310,000; softening point 110 ° C .; glass transition temperature -23 ° C .; elastic modulus 17 kgf / cm ² ; hardness 63.
(JISA); Tear strength 42 kg / cm ² VYHH ³ derived from Union Carbide Typark derived from Ishihara Sangyo ⁴ Irganox derived from Ciba Geigy

The applied solution was heated to a temperature of 120 ° C. (80 to 1
20 ° C. is an effective range) and dried to a thickness of about 50 micrometers to form a binder layer.

Polyester knitted woven fabric (Toray knitted woven fabric No. 501) which is a polyester woven fabric subjected to calendering
Was laminated on top of this layer of binder; a temperature of 100 ° C. and a pressure of 5 kgf / cm ² were used (70-100 ° C. and 3-5 kgf / cm ² are effective areas). In such a case, a two layer protective film 17 comprising an upper polyethylene layer and a lower polyethylene terephthalate layer is pre-laminated on the bottom surface of the fabric.

In another embodiment, a spunbonded nonwoven fabric (Unitika nonwoven fabric S1) comprising bicomponent fibers having a polyethylene layer on a polyethylene terephthalate core.
003WDO) was laminated to this layer of binder instead of the polyester woven fabric described above. The cloth was previously corona treated. Stacking temperature and pressure are 10 each
The temperature was 0 ° C. and 5 kgf / cm ² . In this example, the protective film 17 was not used. In both examples,
The carrier sheet 18 is then stripped off and a cover film 1 of an extruded 75 micrometer thick ethylene-acrylic acid polymer (Primacor 3440 supplied by Dow Chemical) containing a UV absorber.
4 was placed in contact with the exposed surface of the microsphere. This assembly is then heated to 160 ° C. with an upper rolling roll made of smooth-faced rubber, and a lower metal heated to 80 ° C. and having a mesh-like embossing intersecting in a hexagonal pattern. It was subjected to embossing pressure using a roll. The rolls were pressed together and a pressure of 3-5 kgf / cm ² was applied, then the assembly was passed between the rolls at a rate of 3 meters / minute. Then, after this embossing step, the protective film 1
I removed 7.

Then, the reinforced retroreflective sheeting obtained was subjected to a series of tests shown in Table 1.

[0028]

[Table 1]

⁵ Edge integrity and no frayed thread ⁶ CPL is candela / lux / square meter ⁷ 30 ° C. and 0% RH (12 hours) and 80 ° C. and 50%
Alternating with RH (12 hours) manufactured by ⁸ Suga Test Machine Co., Ltd .; black panel temperature of 63 with a water jet of 18 minutes per 120 minutes.
Operate to ± 3 ° C and provide UV light exposure for 750 hours

In yet another embodiment, a polyester woven fabric (100% polyester, 85.5 × 60 construction,
A weight of 3.1 ounces / square yard, crimped bulky system supplied by Milliken, using 1/150/34 warp and weft) was used as the reinforcing sheet. In this embodiment,
Lamination of the fabric to the bottom of the binder layer and embossing of this assembly onto the cover film were performed simultaneously. The upper rolling roll was not heated and the lower metal roll was heated to 215 ° C.

It will be apparent to those skilled in the art that various modifications and variations of the present invention do not depart from the scope of the invention.

[Brief description of drawings]

FIG. 1 is a top view of a part of a reflection sheet of the present invention.

FIG. 2 is an enlarged cross-sectional view of an intermediate assembly produced during the production of the reflection sheet of the present invention.

FIG. 3 is an enlarged cross-sectional view of a part of an apparatus used for manufacturing the reflection sheet of the present invention and the reflection sheet of the present invention.

[Explanation of symbols]

 10 ... Retroreflective sheet 11 ... Binder layer 12 ... Microsphere 13 ... Mirror-like retroreflective film 14 ... Cover film 15 ... Bonding line 16 ... Reinforcement sheet 17 ... Protective film 18 ... Carrier sheet 18a ... Paper layer 18b ... Polyethylene layer 19 ... Intermediate product 20 ... Construct 21,22 ... Surface plate or roller 24, 25 ... Surface plate or roller 26 ... Ridge 27 ... Cell

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[Procedure amendment]

[Submission date] January 13, 1994

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0018

[Correction method] Change

[Correction content]

Fabrics are particularly useful as the reinforcing sheet of the present invention because they are durable and have high tensile strength; the binder penetrates the weave of the fabric to provide good adhesion. Because it can be reached; since it is possible to use a plasticizer-free fabric which can give rise to the problem of weakening the adhesion. Polyester spunbond fabrics are also particularly useful;
It consists typically comprise a polyethylene terephthalate core bicomponent fibers having a polyethylene or polypropylene layer softens at a temperature lower than the polyethylene terephthalate core. Polymer films impart alternativeness to fabrics for several purposes.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Name of item to be corrected] 0023

[Correction method] Change

[Correction content]

Parts by weight thermoplastic polyurethane resin ¹ 16.99 vinyl chloride / vinyl acetate copolymer ² 6.73 titanium dioxide ³ 7.00 antioxidant ⁴ 0.48 stearic acid 0.48 methyl ethyl ketone 49.49 cyclohexanone 17.88 ¹ Takeda Badish Urethane Industry Co., Ltd. Tokyo, commercially available Elast ET1145; 4,4-diphenyl
Reaction product of methane diisocyanate and polyester type polyol comprising tetraethylene glycol and adipic acid; number average molecular weight 140,000 and weight average molecular weight 310,000; softening point 110 ° C .; glass Transition temperature -23 ℃; Elastic modulus 17kg
f / cm ² ; hardness 63 (JIS A); tear strength 42 kg /
cm ² Union Carbide derived VYHH ³ Ishihara Sangyo derived Thai Park ⁴ Ciba Geigy derived Irganox

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0026

[Correction method] Change

[Correction content]

In another embodiment, a spunbonded nonwoven fabric (Unitika nonwoven fabric S1) comprising bicomponent fibers having a polyethylene layer on a polyethylene terephthalate core.
003WDO) was laminated to this layer of binder instead of the polyester woven fabric described above. The cloth was previously corona treated. Stacking temperature and pressure are 10 each
The temperature was 0 ° C. and 5 kgf / cm ² . In this example, the protective film 17 was not used. In both examples,
The carrier sheet 18 is then stripped off and a cover film 1 of an extruded 75 micrometer thick ethylene-acrylic acid polymer (Primacor 3440 supplied by Dow Chemical) containing a UV absorber.
4 was placed in contact with the exposed surface of the microsphere. This assembly is then heated to 80 ° C. with an upper rolling roll of smooth surface rubber, and a lower metal heated to 160 ° C. and having mesh-like embossments intersecting in a hexagonal pattern. It was subjected to embossing pressure using a roll. The rolls were pressed together and a pressure of 3-5 kgf / cm ² was applied, then the assembly was passed between the rolls at a rate of 3 meters / minute. Then, after this embossing step, the protective film 1
I removed 7.

[Procedure amendment 4]

[Document name to be amended] Statement

[Name of item to be corrected] 0029

[Correction method] Change

[Correction content]

[0029] ⁵ lack ⁶ CPL integrity and frayed yarns of edges, candelas / lux / square meter is ⁷ - 30 ° C. and 0% RH (12 hours) and 80 ° C. and 50
% RH (12 hours) produced from alternating ⁸ Suga Test Instruments Co. and; while denoted by the 120 minutes per 18 minutes of water jet, a black panel temperature of 63
Operate to ± 3 ° C and provide UV light exposure for 750 hours

[Procedure Amendment 5]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 3

[Correction method] Change

[Correction content]

[Figure 3]

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor, Belarus Crecia Reitl, Minnesota 55133-3427, St. Paul, P., USA. Oh. Box 33427

Claims (12)

[Claims] 1. A reinforced encapsulating lens type retroreflective sheet, comprising: (1) a layer of a binder having a retroreflective component partially embedded on its upper surface; (2) this retroreflective configuration. A transparent cover sheet positioned with space from the layers of the element; (3)
The binder layer and the cover sheet are bonded to each other,
And a retroreflective component forming a number of cells hermetically sealed therein, comprising a binder impressed from the layer side of the binder and in contact with the cover sheet And (4) a net-like narrow bond line; and (4) permanently and directly attached to the bottom surface of the binder and embossed with the binder layer to form the bottom surface of the binder layer. A retroreflective sheeting comprising: a reinforcing sheet conforming to the embossed shape of. 2. The retroreflective sheeting of claim 1, wherein the reinforcing sheet comprises a fabric and the binder penetrates the weave of the fabric from the layer of binder. 3. The retroreflective sheet according to claim 1, wherein the cover sheet comprises a polyolefin resin. 4. The polyolefin resin is ethylene-
The retroreflective sheeting according to claim 3, comprising an acrylic acid polymer. 5. The retroreflective sheeting of claim 1, wherein the binder comprises polyurethane. 6. The cover sheet comprises a polyolefin-based resin, and the surface of the cover sheet in contact with the binder is covered with a polyurethane base layer,
The retroreflective sheet according to claim 5. 7. The retroreflective sheet according to claim 2, wherein a protective film covers the bottom surface of the reinforcing cloth. 8. The protective film comprises an upper layer and a lower layer, the upper layer uses a thermosoftening material, and the protective film is heat laminated to the reinforcing fabric by the thermosoftening material. The retroreflective sheet described in. 9. The retroreflective sheeting of claim 2, wherein the binder layer is about 25-50 micrometers thick. 10. A method of making a reinforced retroreflective sheeting, comprising: (1) forming a layer of binder on the upper surface of which a retroreflective component is partially embedded; (2) this binder. A reinforcing sheet on the bottom of this layer; (3) overlaying a transparent cover sheet on this layer of retroreflective component; and (4) a net-like heat and pressure towards the bottom of this reinforcing sheet. Is applied, whereby the reinforcing sheet is embossed, and further the binder is brought into partial contact with the cover sheet along the mold from the binder layer side, whereby the binder layer and the cover sheet are applied. An integrated article in which the reinforcing sheet forms a number of cells which are bonded together and whose retroreflective component is hermetically sealed, and whose reinforcing sheet follows the embossed shape of the layer of binder. Person who is characterized by; . 11. The method of claim 10, wherein the reinforcing sheet is heat and pressure laminated to the bottom surface of the layer of binder prior to applying heat and pressure for embossing. 12. The reinforcing sheet comprises a fabric,
The method for producing a retroreflective sheet according to claim 11, wherein the binder penetrates from the layer of the binder into the texture of the cloth.